The American Society for Testing and Materials (ASTM) has devised a test procedure for determining the resistance of protective clothing materials to permeation by hazardous liquid chemicals, which has been published as ASTM Designation F739-81. This procedure was developed to protect workers involved in the production, use, and transportation of liquid chemicals, who are, and can be exposed to numerous compounds capable of causing harm upon contact with the human body. The deleterious effects of these chemicals can range from acute trauma, such as skin irritation and burn, to chronic degenerative disease, such as cancer. Since engineering controls may not eliminate all possible exposures, attention is often placed on reducing the potential for direct skin contact through the use of protective clothing that resists permeation, penetration, and degradation.
The resistance of a protective clothing material to permeation by a hazardous liquid chemical is determined by measuring the breakthrough time, then monitoring the subsequent permeation rate of the hazardous liquid through the clothing material.
In the ASTM permeation test cell, the clothing material acts as a barrier separating the hazardous liquid chemical from a collecting medium. The collecting medium, which can be a liquid or a gas, is sampled and analyzed quantitatively to identify the concentration of hazardous chemical in it and thereby the amount of hazardous chemical that has permeated the barrier as a function of time after initial liquid contact.
This method is normally used to evaluate flat specimens from finished items of protective clothing and from materials that are candidates for items of protective clothing. Finished items of protective clothing include gloves, arm shields, aprons, suits, hats, boots, respirators, and the like.
The phrase "specimens from finished items" encompasses seamed and other discontinuous regions as well as the usual continuous regions of protective clothing items.
By measuring breakthrough time, this method is used to estimate the duration of maximum protection provided by a protective clothing material under the condition of continuous contact. By measuring the permeation rate, this mmethod can be used to identify protective clothing materials that limit potential exposures to acceptable steady-state dermal contact levels.
The ASTM currently recommends the use of an all glass permeation cell as described in its aforementioned standard F739-81. However, this cell requires relatively large volumes (approximately 60 mL) of liquid for a single evaluation, and requires as well relatively large pieces of test material (approximately 20 cm.sup.2).
In addition, the all glass construction of the ASTM cell renders it easily damaged. Moreover, when ASTM methodology is used, a total of at least 180 mL of liquid is necessary, since triplicate analyses are required. Such volumes are dangerous when working with hazardous chemicals.
Furthermore, because of the large volume of liquid required, testing of inherently expensive or scarce chemicals tend to be prohibited by the current ASTM cell.
The aforesaid ASTM standard designation F739-81 is incorporated herein by reference for the purposes of comparison.